error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:14:11
   |
LL | fn fun(x: &mut &mut u32) -> bool {
   |           ^^^^^^^^^^^^^
   |
   = note: `-D clippy::mut-mut` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::mut_mut)]`

error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:31:17
   |
LL |     let mut x = &mut &mut 1u32;
   |                 ^^^^^^^^^^^^^^

error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:46:25
   |
LL |     let mut z = inline!(&mut $(&mut 3u32));
   |                         ^
   |
   = note: this error originates in the macro `__inline_mac_fn_main` (in Nightly builds, run with -Z macro-backtrace for more info)

error: this expression mutably borrows a mutable reference. Consider reborrowing
  --> tests/ui/mut_mut.rs:33:21
   |
LL |         let mut y = &mut x;
   |                     ^^^^^^

error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:37:32
   |
LL |         let y: &mut &mut u32 = &mut &mut 2;
   |                                ^^^^^^^^^^^

error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:37:16
   |
LL |         let y: &mut &mut u32 = &mut &mut 2;
   |                ^^^^^^^^^^^^^

error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:42:37
   |
LL |         let y: &mut &mut &mut u32 = &mut &mut &mut 2;
   |                                     ^^^^^^^^^^^^^^^^

error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:42:16
   |
LL |         let y: &mut &mut &mut u32 = &mut &mut &mut 2;
   |                ^^^^^^^^^^^^^^^^^^

error: generally you want to avoid `&mut &mut _` if possible
  --> tests/ui/mut_mut.rs:42:21
   |
LL |         let y: &mut &mut &mut u32 = &mut &mut &mut 2;
   |                     ^^^^^^^^^^^^^

error: aborting due to 9 previous errors